Electric brake.



PATBNTEDAUG, 25, 1903.

' F. c. NBWBLL.

ELECTRIC BRAKE. APPLIOATION'I'ILED nnd. a1. 1902.

' 1 0 MODEL.

Atty.

i\l'o; 737,263.

UNITED STATES iatented August :25, I

PATENT OFFICE.-

FRANK o. NEWELL, OF WILKINSBUBG, PENNSYLVANIA, AssIeNoR' TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF PrrTsBuRe, PENNSYLVANIA,

A oORPORATIoN OFTENNSYLVANIAp ELECTRIC BLRAKE.

SPECIFICATION forming part of Letters Patent No. 737,265, dated August 25,- 1903. Application filed December 31, 1902. Serial No. 137,299. (No model.)

To all whom it may cancer-m 4 Be it known that I, FRANK C. NEWELL, a citizen of the United States, residing in Wilkinsburg, in the county of Allegheny, State 5 of Pennsylvania, have invented a certain new and useful Improvement in Electric Brakes, of which improvement the following is a specification. i

This invention relates to electric-brakes for car sand particularlyto electrically-propelledcars in which the motors are used as braking generatorsfor supplying the local'brake=circuit. I-Ieretofore'it has usually been the practice to provide these cars with a power-controller, a reversing-switch, and a braking-con troller, the latter being adapted to connect up the motors'to act as generators an d'to control the current so generated in a local brake-circuit. This form of equipment has always been arranged for braking only when the car is moving in the direction for which the reversing-switch is set. It sometimes happens, however, that a car will start to move in a direction opposite to that for which the revers- '2 5 ing-switch is set-as, for instance, on agrade where the motorman loses control of the car and it starts to run backward downgrade. If. the brake switch or controller is then thrown without first moving the reversing-switch, it

will have no effect, since the leads are connected up in the reverse direction to that in which the armatures are revolving, and no current will be generated in the brake-circuit. This condition often leads to serious acci- 3 5 dents,since the motorman rarely has suflicient knowledge or presence of mind to throw the reversing-switch at such times.

The principal object of this present invention is to provide an automatic reversing- 40 switch which will always set up the proper combination of circuits for braking when the car is moving in either direction, so that the brake-switch or controller may always be depended upon for stopping the ear.

Another object is to so arrange the circuits and brake-switch contact-points that the automatic reversing device will in no way interfere with the proper manipulation of the power controller and reversing switch for running the car. I

In the accompanying drawings, Figure lis a circuit-diagram of a car equipment provided with two motors, a power-controller, a

reversing-switch, a braking-controller, and

car only are shown; but it will be understood that the circuits are extended to a duplicate set of these devices at the opposite endof the car in the usual way.

The, running or power controller 0 is of the ordinary series-parallel type, having contactbars 13, 14, 16, 17, 18, 20, and 21 for making contact with the stationary fingers when run= ning with the motors in series and other bars 23 to 27, inclusive, for use in running with the motors in'parallel. The reversing-switch D is providedwith the usual contact-bars l to 12, all of which construction is well known to those familiar with the art.

The improved braking-controller B has one set ofcontact-bars, 28 to 32, which are adapt.

v.e'dto-make contactwith the stationary fingers or points when this controller or switch is in position for running, while another set of bars, 33 to 47, are arranged to engage the stationary contact-points when the switch is in the braking'positionsv As a preferred form of automatic reversing-switch K, the same is shown provided with contact-bars 48 to59 and formed in two 5 sections, each of which comprisesa drum M,

.rotatably and slidably mounted on a shaft or spindle N, which is securedin the end of ar-' mature-shaft U or some other rotating part of the can On the spindle'is' pivoted a pair of arms 0, carrying the centrifugalweigh ts 0r balls P at one end and bearing against the drum N at the other end. A spring'W nor mally tends to force "the arms toward each other and the drum against the end of the ro tating shaft, thus causing suflioient frictional contact to rotate the drum with the shaft. The springs W are so adjusted that when the car is moving at normal or any predetermined rate of speed the centrifugal force of the balls P will turn the arms upon their pivot and relieve the pressure with which the drum bears against the shaft. The switches are shown in their neutral or open position, with the stationary fingers between the opposite sets of contact-bars, and the drum may also be provided with a projecting pin or lug 60, adapted to engage oppositely located fixed stops 61 and 62, so that the drum can rotate only from one of its positions to the other. It will now be apparent that when the car comes to a stop the speed-controlled device tends to force the friction members of the automatic switch device into contact, so that when the car starts to move the switch will be thrown to one position or the other, according to the direction the car is movin Then as the speed of the car increases the speed controlled device will relieve the pressure between the friction members, and thus prevent excessive wear and resistance, the switch remaining in the position to which it is thrown until the direction of movement of the car is reversed.

The automatic reversing-switch could obviously be used without the speed-controlled device, if desired, and while I have shown a particular form of switch it is to be understood that my invention is not limited thereto, but that any form of automatic reversingswitch operated by the movement of the car maybe used. Various other forms of speedcontrolled devices may also be used in the place of that shown for throwing off the friction-clutch or relieving the pressure between the friction members of the device.

The operation is as follows: It being desired to run the car forward, the hand-operated reversing-switch D and the braking-controller B are set in their corresponding positions and the running-controller G moved to its first point. The current then enters from trolley T to bars 13 and 14, thence by lead B through resistance R, lead 19 to bar 4 on reversing-switch, lead A to bar 29 on the braking-controller, and through armature Aof No. 1 motor, lead A A to bar 30 on the brakingcontroller and to bar 3 on reversing-switch, lead F through field F of No. 1 motor, lead E to bars 21 and 20 on running-controller, lead 15 to bar 2 011 reversing-switch, lead A to bar 31 on braking-controller and to armature A of No. 2 motor, lead A A to bar 32 on braking-controller and to bar 1 on reversingswitch, lead F to field F of No. 2 motor, lead E to bar 28 on braking-controller, and thence to ground G or return-trolley. When the car starts to move, the automatic reversingswitch will immediately be thrown to forward position, with bars 48, 49, 54, and 55 engaging the stationary contact-fingers S, A A, L, A, S AA L and A but this will have no effect upon the running or power circuits, since the leads S, S L, and L are open at the braking-controller. Further movements of the runningcontroller serve to control the current in the usual way. lVhen it is desired to apply the brakes, the running-controller is thrown to off position and the brakingcontroller is moved to first braking position. The current may then be traced as follows: From the armatures of the motors, now acting as generators, by leads A and A to bars 49 and 55, respectively, of automatic reversingswitch, thence by respective leads L and L to contact-bars 38 and 37 on braking-controller, thence to bar 33 and through the resistance R to R, contact-bars 39 and 40 011 brakingcontroller, lead B 0 through brake-magnet coils H to contact-bars 46, 45, and 47 on braking-controller. Here currentdivides, one line returning by lead F to field of No. 1 motor, lead E to bars 44 and 43 on braking-controller, thence by lead S to bar 48 on automatic reversing-switch, and by lead A A back to armature of No. 1 motor. The other branch of the current returns from bar 47 by lead I to field of No. 2 motor, lead E to bars 41 and 42 on braking-controller, lead S to bar 54 on automatic reversing-switch,and by lead A A back to armature of No. 2 motor. Further movement of the brakingcontroller serves to cut out resistance in the brake-circuit in the usual way. If after thus being brought to a stop the car should start to run downgrade backward, the automatic switch K would be immediately reversed and the braking-c011 troller could be used to stop the car, the same as in forward braking. Tracing the course of the current under these conditions, the armatures revolving in the opposite direction from what they were before the current flows from the armatures by leads A A and A A to the respective bars 51 52 and 57 58 of the switch K, thence by leads L and L as before, to the resistance, through the fields,returning by leads S and S to bars 50 53 and 5b 59 on the switch K, thence by the respective leads A and A back to the armature of the motors. It will thus be seen that the automatic reversing-switch always sets itself in position to establish the proper connections for the brake-circuifi no matter in which direction the car may be moving. It will also be noted that when the braking controller is thrown to any of its braking positions the hand-operated reversing-switch D is cut out from the brake-circuit altogether, so that even if switch D should accidentally be thrown by hand during the braking it would interfere in no way with the brake-circuit. After being brought to a stop at any time the car may be started again merely by the usual movements of the controllers.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination on an electric car of one or more motors, a braking switch or controlleradapted to connect up the motor or motors in a local brake-circuit, and a reversing-switch operated by the movement of the car.

2. The combination with one or more generators, of a braking-controller adapted to connect up the generators in a brake-circuit, and a reversing-switch operated by a movable part of the generator.

3. The combination on an electric car of one or more motors, a power-controller, -a handoperated reversing-switch, a braking-controller, an automatic reversing-switch, and means operated by the movement of the car for throwing said automatic switch.

4. The combination on an electric car of one or more motors, a braking-switch for connecting up the motor or motors in a local brakecircuit, an automatic reversing-switch and means having frictional engagement with a rotating part of'the vehicle for operating said reversing-switch.

5. The combination with an automatic reversing-switch and means having frictional engagement with a rotating part of a vehicle for operating said switch, of a speed controlled device for relieving the friction between said parts when the speed exceeds a certain rate.

6. The combination with one or more motors and a braking-switch for connecting up the motor or motors in a local brake-circuit, of an automatic reversing-switch, a friction mechanism operated by the movement of the vehicle for throwing said reversing-switch adapted to cut out the hand-operated reversing-switch when moved to braking position. 8. The combination with one or more motors and a hand-operated reversing-switch, of an automatic reversing-switch operated by the movement of the car and a braking-switch adapted to'cut out the hand-operated reversing-switch when in braking position and to cut out the automatic switch when in running position.

In testimony whereof I have hereunto set w my hand.

FRANK. C. NEWELE. Witnesses:

R. F. EMERY,

Mrs. B. MACDONALD. 

